The shoots are dimorphic, with long shoots (10–40 cm (3.9–15.7 in) long) producing structural branch growth, and short shoots (0.5–5 cm (0.20–1.97 in) long) bearing the flowers; this pattern often developing a 'herringbone' form of branching. The leaves are arranged alternately, 0.5–15 cm (0.20–5.91 in) long, ovate to lanceolate in shape, entire; both evergreen and deciduous species occur.

The flowers are produced in late spring through early summer, solitary or in corymbs of up to 100 together. The flower is either fully open or has its five petals half open 5–10 mm (0.20–0.39 in) diameter. They may be any shade from white through creamy white to light pink to dark pink to almost red, 10–20 stamens and up to five styles. The fruit is a small pome 5–12 mm (0.20–0.47 in) diameter, pink or bright red, orange or even maroon or black when mature, containing one to three (rarely up to five) seeds.^[3][4] Fruit on some species stays on until the following year.

Cotoneaster species are used as larval food plants by some Lepidoptera species including grey dagger, mottled umber, short-cloaked moth, winter moth, and hawthorn moth. The flowers attract bees and butterflies and the fruits are eaten by birds.

Although only a single species is native there, in the UK and Ireland, Cotoneaster species are, along with the related genus Pyracantha, a source of nectar. The red berries are also highly attractive to blackbirds and other thrushes.

Cotoneasters are very popular garden shrubs, grown for their attractive habit and decorative fruit. Some cultivars are of known parentage, such as the very popular Cotoneaster × watereri Exell (Waterer's cotoneaster; C. frigidus × C. salicifolius), while others are of mixed or unknown heritage.^[4]

The following species and cultivars have gained the Royal Horticultural Society's Award of Garden Merit:-

Invasiveness edit

Many species have escaped from cultivation and become invasive weeds where climatic conditions are suitable for them, such as the many Chinese species naturalised in northwestern Europe.^[16] C. glaucophyllus has become an invasive weed in Australia^[17] and California.^[18] C. simonsii is listed on the New Zealand National Pest Plant Accord preventing its sale and distribution because of its invasiveness. On Portland, Dorset, UK, it has become invasive and is regularly culled to prevent damage to the Jurassic Coast.

The genus name Cotoneaster derives from cotoneum, a Latin name for the quince, and the suffix -aster, 'resembling'. The name is correctly masculine, though in some older works it was wrongly treated as feminine, resulting in different name endings for many of the species (e.g.Cotoneaster integerrima instead of Cotoneaster integerrimus).^[3]

The genus is often divided into two or more sections, though the situation is complicated by hybridisation:^[3]

• Cotoneaster sect. Cotoneaster (syn. sect. Orthopetalum). Flowers solitary or up to 6 together; petals forward-pointing, often tinged pink. Mostly smaller shrubs.
• Cotoneaster sect. Chaenopetalum. Flowers more than 20 together in corymbs; petals opening flat, creamy white. Mostly larger shrubs.

All Cotoneaster berries are eaten by many birds. Like most other small, red berries, they are evolved to have birds spread the seeds widely and are not good for humans to eat. The Children's Hospital of Philadelphia lists Cotoneaster berries as poisonous^[19]

Selected species edit

Sources:^{[2][4][16][21][22][23]}

•   Media related to Cotoneaster at Wikimedia Commons
•   Data related to Cotoneaster at Wikispecies
• Multi-access key to the 26 Cotoneaster species found in New Zealand